So will need new tubes, obviously, Ps and bypass caps almost a given. My concern is the spendy transformers.Worse case scenario: one of more transformers might need to be replaced. An equiv power transformer is available at some electronics supply houses for aprox 100, what about the output transformers, with the center channel tap it's not a off the shelf part from digikey etc.

So question is am I creating a problem where one may not exists or are the transformers known to fail easily if a tube dies?

I have never heard of a Mac transformer failing...and I have been in this hobby for 35 years.If anything is wrong with your amplifier, Audio Classics can fix it and I recall a McIntosh specialized tech that posts frequently on the McIntosh forum at Audiokarma.org.